Braking device for a wind-off reel



Filed Dec. 19, 1963 2 Sheets-Sheet 1 March 29; 1966 c. o. l.. NORMAN3,243,137

BRAKING DEVICE FOR A WIND-OFF REEL Filed Dec. 19, 1963 2 Sheets-Sheet 2United States Patent O 3,243,137 BRAKING DEVICE FOR A WIND-OFF REEL CurtOskar Ludvig Norman, Spanga, Sweden, assigner to Arenco Aktiebolag,Vallingby, Sweden, a joint-stock company of Sweden Filed Dec. 19, 1963,Ser. No. 331,737 Claims priority, application Sweden, Jan. 5, 1963, 122/63 Claims. (Cl. 24275.43)

The present invention is related to braking devices for rotatable reels,drums, bobbin spindles or the like, from which a material band `is to bewound oi.

In wind-ott devices of this type it is often required that the tensionin the band or thread wound-off from the reel be maintained as constantas possible during the windingoff and that the reel be immediatelystopped in case of disruption or breakage of the band. For this purposea braking device for the reel is necessary, which can automaticallycontrol the braking of the reel so that the band is wound-off from thereel with a constant tension, said braking device -being also eifectiveto bring the reel to'a rapid standstill in case of disruption of theband. Various lbraking devi-ces for this purpose are known in the art,but particularly for wind-ott devices, where the desired tension in thewound-off material band is -comparatively small and the permissiblevariations in this tension are small, as, erg.,

for the winding-off of band-tobacco, thin paper strips,

textile threads and similar materials from a bobbin, no simple brakingdevice has hitherto been available, which has -been capable ofsufficiently evenly and continuously varying the braking of the wind-oitreel in dependence of the tension in the wound-ott .material band and ofrapidly stopping the reel in case of disruption of the band.

An object of the present invention is, therefore, to provide a brakingdevice for a rotatable wind-off reel or a similar device for band-shapedmaterial, which is of a simple -construction and is capable of evenlyand continuously varying the braking of the wind-oil reel in dependenceon the tension in the wound-ott material, even if this tension is smallso as to maintain the tension substantially constant, while the brakingdevice also can very rapidly stop the wind-oft reel in case ofdisruption of the wound-ofi material band.

According to the invention there is provided a braking device for arotatable wind-ofi reel for band-shaped material which a rotatableroller having -a portion of its periphery in contact with a rotatingpart of said reel and being angularly displaceable about an axis throughthe point of contact between the periphery of the roller and saidrotating part of said reel and substantially perpendicular to the axisof rotation of the roller, guiding means for said material bandwound-off from the reel, said guiding means being displaceable under theinuence of the tension of the material band running over said guidingmeans and a counter-acting force, said guiding means and said rollerbeing mechanically interconnected through motion transferring means insuch ya way that said roller is displaced about said displacement axisin dependence on the displacement of said guiding means, in such adirection that the axis of rotation of the roller is displaced towards aposition parallel with the direction of movement of said rotating partof the reel, when the tension in the wound-off material band decreases,and towards a position perpendicular to the direction of movement ofsaid rotating part, when the tension in the material band increases.

The invention and ,its mode of Operation will be further described withreference to the accompanying drawing, which by way of example shows abraking device according to the invention for a bobbin spindle for thewinding-off of band-tobacco from a bobbin mounted on 3,243,137 PatentedMar. 29, 1966 ice the spindle. 'In the drawing FIG. 1 is a side viewtrom the outer end of the spindle, showing the bobbin spindle with abobbin mounted thereon and the braking device; FI'G. 2 is a top viewperpendicular to the shaft of the spmdle and FIG. 3 is a side viewperpendicular to the shaft of the spindle.

The drawing shows a spindle shaft 1, which is rotatably journalled -in amanner not shown in the drawing and on the outer end of which a bobbin 2with a band 3 of band-tobacco is mounted. The spindle 1 is provided witha circular disc 4, which is perpendicular to the axis of rotation of thespindle and rotating together with the spindle. The disc 4 serves as alateral support for the bobbin 2 on the spindle and cooperates with thebraking device according to the invention. The band 3 is pulled bysuitable means not shown in the drawing in the direction of the arrow 5.and is thus wound-oit the bobbin 2, which will rotate together with thespindle 1 in the direction of the arrow 6.

The braking device according to the 4invention comprises a guide pulley7, over which the wound-off band 3 runs. The pulley 7 is rotatablyjournalled in `one end of a doublearmed lever 8, which by means of apivot 9 is pivotally mounted in a stationary support 10. The oppositeend of the double-armed lever 8 is provided with a weight 11, whichtends to swing the lever 8 in a counter-clockwise direction in FIG. 1,about its pivot 9. This is, however, counteracted by the tension in thematerial band 3 running over the guide pulley 7, as this tension isapplying a clockwise moment to the lever 8 about its pivot 9.

When the toibacco-band 3 is wound-oit from the bobbin 2, the lever 8will consequently assume a position of equilibrium somewhere between thestationary limit stops 17 fand 18, which position is dependent on theactual tension in the wound-olf band 3. The weight 11 is preferablydisplaceable along the lever 8 so that the tension in the wound-off band3 can be adjusted to a preselected value. On the lever S a console 12 ismounted, on which a roller 13 is journalled so that it is freelyrotatable. The periphery of the roller 13 is preferably provided wit-h arubber ring 14 or the like and is kept in contact with one side of thedisc 4 by a coil spring 15 acting between the Astationary support 10 anda ring 16 on the pivot 9 of the lever 8. Preferably the ring 16 isdisplacea-ble along the pivot 9 so that the tension of the spring 15 andthus the Contact pressure between the roller 13 and the disk 4 can Ibeadjusted. As shown in the drawing, the roller 13 is so mounted on theconsole 12, that the point of contac-t between the periphery of theroller 13 and the side surface of the disc 4 is disposed substantiallyon the pivot axis ofthe lever S, due to which the roller 13 will beangularly displaced about this axis, when the lever is moving betweenthe limit stops 17 and 18 in dependence on any variations in the tensionin the wound-oftr band 3.

When the spindle 1 .and thus the disc 4 are rotating in the direction ofthe arrow 6, while the band 3 is woundoi from the bobbin 2, the roller13 will evidently roll on the disc 4. In the position of the lever 8shown in full lines in the drawing the plane of rotation of the roller13 is substantially tangential to the direction of rotation of the disc4, due to which a pure rolling motion of the roller 13 on the disc 4will exist. In this position there is consequently no mutual slipbetween theperiphery of the roller 13 and the disc 4 and as the rolleris freely rotatable, eg., by means of ball bearings or the like, theroller 13 has in this position no braking effect upon the disc 4, t-hespindle 1 and the bobbin 2. As the contact between the periphery of theroller 13 and the disc 4 is not normally restricted to a point, the axisof rotation of the roller 13 is preferably somewhat oblique relative tothe plane of the disc 4 so that in each point within the Contact surfacebetween the periphery of the roller and the disc 4 the periphery of theroller and the disc will have the same speed.

If in this position of the braking device the tension in the wound-oftband 3 decreases, the lever 8 will swing in a counter-clockwisedirection in FIG. 1 about its pivot 9 towards the stationary limit stop11. Due to this swinging movement of the lever 8, the roller I13 will bedisplaced so that its direction of rotation is no longer approximatelyparallel with the direction of rotation of the disc 4. Consequently, apure rolling motion of the roller 13 on the disc 4 will no longer exist,but a mutual slip will arise between the periphery of the roller 113 andthe disc 4, so that a friction force will arise at the cont-act pointbetween the roiler and the disc. This friction force is directedperpendicularly to the direction of rotation of the roller 13. Themagnitude of the friction force is primarily determined by the contactpressure of the roller 1,3 against the disc 4 and of the frictioncoefficient between the periphery of the roller and the disc 4, but issubstantially independent of the magnitude of the angular displacementof the roller 13, i.e., of the position of the lever 3 between the limitstops 17 and 18. Of this friction force, however, only the componenttangential to the axis of rotation of the disc 4 will have any brakingeffect upon the disc 4 and thus the spindle 1, whereas the component ofthe friction force directed radially relative to the axis of rotation ofthe disc 4 will not have any braking effect. The component of thefriction force, which is active for the braking of the disc 4 and thespindle 1 and thus the bobbin 2, will evidently increase continuouslyfrom zero, when the lever 8 moves from the limit stop 1 8 towards thelimit stop 17. Due to the braking of the spinde 1 and the bobbin 2mounted thereon, the tension in the wound-off band 3 will increaseagain, until an equilibrium is reached between the tension and themoment applied to the lever by the counter-weight 11 and this positionof equilibrium will correspond to the preselected desired tension in theband 3.

In case of disruption of the wound-offv band 3 the lever 8 will swingunder the influence of the counter-weight 1,1r to the end positiondetermined by the stationary limit stop 17 so that the maximum brakingVeffe-ct arises and the spindle 1 with the bobbin 2 mounted thereon isimmediate- 1y stopped.

The braking device according to the invention has consequently thecharacteristic feature thatvit can smoothly and continuously control the-braking force within a wide range from zero to a preselected maximumvalue in de pendence on the tension in the wound-olf band. The brakingdevice can be used for very small tensions in the wound-01T band and canbe made very sensitive for small variations in the tension, asa verysmall for-ce is required for swinging the lever 8 about its pivot 9 andthis: force is substantially completely independent of the magnitude ofthe braking force. This is due to the fact that the braking force isinfiuencing the rotating brake roller 1,3 and thus the lever 8 at asingle point, which is disposed on the pivot axis of the lever, wherebythe braking force cannot apply any moment o-n the lever. i

Although the braking device according to the inven-A tion shown in thedrawing and described above has proven to be very advantageous for abobbin spindle of the illustrated type, it is evident that several otherforms of the invention are possible and may even be preferable for othertypes of wind-off reels. It is obvious, eg., that the lever 8 can beiniiuenced by a spring means instead of the counter-weight 11. Furtherit is not necessary that the brake roller 13 be in contact with asurface on the reel,

which is perpendicular to the axis of rotation of the reel, but it mayinstead be in contact with any other rotating surface of the reel, forexample, directly against the shaft of the spindle 1 in the embodimentshown in the drawing. In this case another type of transfer mechanism isof course necessary between the brake roller 13 and the guide pulley 7.It is essential, however, that the brake roller is au-gularly displacedin such a way in dependence on the movement of the guide pulley that theaxis of rotation of the brake roller is displaced towards a positionparallel with the direction of movement of the rotating part of thewind-off reel, against which the brake roller is in contact, when thetension in the Wound-off material band decreases, and towards a positionperpendicular to the direction of movement of saidV rotating part, whenthe tension in the band increases.

I claim:

1. In combination, a rotatable reel for a band of material and a brakingdevice for said reel, said braking device comprising a rotatalble rollerhaving a periphery in contact with a rotating part of said reel, saidroller being angularly displacea'ble about an axis through the point ofContact between the periphery of the roller and said rotating part ofthe reel and substantially perpendicular to the axis of rotation of saidroller, guide means for the passage of said band of material which iswound olf said reel, said guide means being displaceable under theinfluence of the tension in the wound-oit band running over said guidemeans and a counter-acting force, motion transferring meansinterconnecting said guide means and said roller in such a way that theroller is angularly displaced about said displacement axis in dependenceon the displacement of said guide means so that the axis of rotation ofthe roller is displaced towards a position parallel with the directionof movement of said rotating part of the reel, when the tension in theband decreases, and towards a position perpendicular to the direction ofmovement of said rotating part, when the tension in the band increases.

2. The combination as claimed in claim 1, wherein said roller is pressedagainst said rotating part of the reel by a substantially constantspring force.

3. The combination as claimed in claim 1, wherein the periphery of saidroller is provided with a friction layer.

4. The combination as claimed in claim 1, wherein said motiontransferring means includes a lever pivotable about a stationary axis,said guide means -being mounted on said lever such that the tension inthe band running over said guide means applies a moment to said leverabout said stationary axis thereof, and means for applying acounter-acting moment to said lever, said roller lbeing rotatablymounted on said lever with its displacement axis substantially coaxialwith said stationary axis of the lever.

5. The combination as claimed in claim 4, wherein said roller is incontact with a rotating surface of said reel substantially perpendicularto the axis of rotation of the reel.

References Cited by the Examiner UNITED STATES PATENTS 2,205,641 6/1940wilson 242-8452 2,534,130 12/1950 Hunt 242-155 2,661,914 12/1953 Thom242-156 X 2,706,602 4/1955 spears 242-8452 MERVIN STEIN, PrimaryExaminer.

VJ. S. BURDEN, Assistant Examiner.

1. IN COMBINATION, A ROTATBLE REEL FOR A BAND OF MATERIAL AND A BRAKINGDEVICE FOR SAID REEL, SAID BRAKING DEVICE COMPRISING A ROTATABLE ROLLERHAVING A PERIPHERY IN CONTACT WITH A ROTATING PART OF SAID REEL, SAIDROLLER BEING ANGULARLY DISPLACEABLE ABOUT AN AXIS THROUGH THE POINT OFCONTACT BETWEEN THE PERIPHERY OF THE ROLLER AND SAID ROTATING PART OFTHE REEL AND SUBSTANTIALLY PERPENDICUALR TO THE AXIS OF ROTATION OF SAIDROLLER, GUIDE MEANS FOR THE PASSAGE OF SAID BAND OF MATERIAL WHICH ISWOUND OFF SAID REEL, SAID GUIDE MEANS BEING DISPLACEABLE UNDER THEINFLUENCE OF THE TENSION IN THE WOUND-OFF BAND RUNNING OVER SAID GUIDEMEANS AND A COUNTER-ACTING FORCE, MOTION TRANSFERRING MEANSINTERCONNECTING SAID GUIDE MEANS AND SAID ROLLER IN SUCH A WAY THAT THEROLLER IS ANGULARLY DISPLACED ABOUT SAID DISPLACEMENT AXIS IN DEPENDENCEON THE DISPLACEMENT OF SAID GUIDE MEANS SO THAT THE AXIS OF ROTATION OFTHE ROLLER IS DISPLACED TOWARD A POSITION PARALLEL WITH THE DIRECTION OFMOVEMENT OF SAID ROTATION PART OF THE REEL, WHEN THE TENSION IN THE BANDDECREASES, AND TOWARD A POSITION PERPENDICUALR TO THE DIRECTION OFMOVEMENT OF SAID ROTATING PART, WHEN THE TENSION IN THE BAND INCREASES.